A polyp is generally a growth that projects from a membrane in the body. The shape of a polyp is often described as pedunculated or sessile. Pedunculated polyps grow on stalks, while sessile polyps may have broad bases and a flat appearance. Often, polyps form on mucous membranes such as those lining the colon, bladder, uterus, cervix, vocal cords, and/or nasal passage and protrude into a body cavity. Polyps are problematic in that they may block a passage, and/or may become cancerous.
Endoscopic polypectomy procedures are effective in removing pedunculated polyps; however, sessile polyps may be problematic. For example, because of their flat, diffuse appearance, sessile polyps may be difficult to snare and excise with electrocautery. To facilitate excision of some polyps, saline or other materials may be injected into the submucosa of a polyp to create an artificial cushion that raises the polyp.
Means for introducing injection solutions into a polyp include endoscopic methods which may, in embodiments, include the use of catheters and/or cannulas. As is within the purview of those skilled in the art, cannulas may include tubular, flexible, surgical instruments for withdrawing fluids from (or introducing fluids into) a cavity of the body. Cannulas may have a single lumen or may have multiple lumens; multi-lumen cannulas, including dual lumen cannulas, are also within the purview of those skilled in the art.
Various configurations for multi-lumen catheters and/or cannulas are also known. For example, U.S. Pat. No. 4,385,631 discloses a hemodialysis catheter having two circular lumens arranged side by side. U.S. Pat. No. 4,099,528 discloses a coaxial double lumen cannula and U.S. Pat. No. 4,493,696 describes a coaxial double lumen catheter.
There remains room for improvement in methods for performing endoscopic polypectomy procedures, and especially to enhance the ability of a physician to determine whether or not a polyp is cancerous during the polypectomy procedure.